Apparatus for heating a fluid by means of solid fuel



M. C. K. DE PORAY APPARATUS FOR HEATING A FLUID BY MEANS 0F SOLID FUEL 2 Sheets-Sheet l Filed Sept. 18, 1945 E ww Rm //V VEA/702 w---WBTWW M. C. K. DE PORY APPARATUS FOR HEATING A FLUID BY MEANS 0F SOLID FUEL 2 Sheets-Sheet 2 Filed sept. 18, 1945 Patentecl May 22, 1951 UNITED STATES ATENT CFFICE Application September 18, 1945, Serial No. 617,118

In France April 29, 1941 3 Claims. l

The object of this invention isto devise an apparatus for heating a uid by means of solid fuel.

According to one feature of the invention, the device comprises a tubular hearth in which part a total combustion of the gaseous elements evolved from the fuel taires place by means of 'a secondary draught entry, one or several elements transferring heat to the heated uid being arranged around said tubular hearth, whose entrance opens into a fuel containing tank, in which an inrush of primary draught ensures combustion luider such conditions that the resulting gaseous compounds still retain a certain amount of combustible gases as they enter the tubular hearth, discharge from which is eifected into the whole group of heat transmitting elements. Combustion of the gases is completed in the tubular hearth, as will hereinafter appear.

According to another feature of the invention,.

a spinning motion is imparted to the gases by means of devices such as tangential tuyres or blades, helicoidal inclines, and so forth, fitted on the tubular hearth or at the entry thereof.

Further features of the invention will become apparent from the following descrip-tion, referring to the accompanying drawings which show by Way of example different embodiments of the invention and in which:

Fig. 1 diagrammatically shows in vertical section, the theoretical arrangement of an apparatus according to the invention.

Fig. 2 is a vertical section through the practical embodiment of a vertical boiler according to the invention.

Fig. 3 is a corresponding plan view.

Fig. s is a horizontal sectional View through line llll of Fig. 2.

Fig. 5 is a vertical section through a practical embodiment of a horizontal boiler according to the invention, and

Fig. 6 is a vertical section of a hot-air stove according to the invention.

Referring to Fig. l, ESI is a main body containing fuel E82 and whose central portion contains an annular chamber E03 inside which a tubular hearth ll is arranged, a space El@a being provided between the tubular hearth and the walls llt of said chamber. Said tubular hearth is assembled to the base of the annular chamber by means of a head-plate H35 through which the tubular hearth is run so as to form an annular pre-combustion chamberV tt. A conduit Ill opens into chamber litt. A group of tubular iiues li'l opens into a smoke-box H2 connected to a stack (not shown) through a pipe H3.

A pipe H4 permits the discharge of tubularhearth 54 to directly communicate with the stack by means of a pipe H5 comprising a damper llt.

At the base of the apparatus a grate with steps HS is shown by way of example, through which the primary draught is admitted.

l which will preferably open tangentially into the pre-combustion chamber H35 where the mixing of the gases with air takes place. I

The gases in tubular hearth |64 are then discharged and flow downwards, into annular chamber I ille then upwards into tubes l'l, smoke-box H2 and out through pipe H3.

Cold water is let in by pipe m8, rises through the annular chamber |63 and flows out heated, through pipe iil.

By opening damper l le, at starting or in other special cases, it is possible to convey directly from tubular hearth |84 to the stack, unconsulned or over-cool gases, and thus avoid sooting of the boiler.

The primary hearth Ill providing only an incomplete combustion, there will be no objection to lowering its temperature to avoid the production of slag. This result may be achieved, for example, by mixing the primary air with smoke or steam.

It can be seen that this type of boiler can be be readily used with pulverized fuel, the grate H8 being removed and the mixture of air and fuel-dust being injected into chamber Ill@ which acts as a pre-combustion chamber.

A description of an apparatus construotedaccording to the principles of this invention is given below and two examples of practical embodiments o the invention follow.

Referring to Figures 2, 3 and 4, representing a type of vertical steam boiler built according to the principle described above, in Fig. 2, I is the boiler body ending in a domed head-plate 2. The heating surfaces comprise a flue 3 connected to body l by a row of rivets 4, a casing or heattransferring element l ending in a domed head plate s. and smoke tubes l2. These are mounted on a lower tubular head-plate 6 and a cast-steel crown i3 welded to domed head-plate 2 so as to ensure proper caulking in spite of the domed head plates incline.

Primary hearth It is hand iired onto a grate it consisting in two sections which may be tilted to permit a ready cleaning of the hearth; cleaning is also facilitated by a clearance space l5 provided between the grate and the boiler. The body l comprises, at its lower end, an annular plate 5 projecting towards the inside of the primary hearth !!l.

Above the primary hearth is a refractory vault l1 suspended from fire-crown i8 which also sup- 3 ports the secondary hearth consisting in a tubular body 24 whose entry is fitted with a diffuser 25 out of refractory material, presenting a reduced sectional area to the iiow of gases.

Two tangential tuyres 25, Figures 2 and 3, with adjustable sections and an additional inlet 28, Figure 2, are provided on the redoor 29 to provide an entry for secondary air. Tangential inclines 21, cast in the same piece with the vault, are provided to give the gases a spinning motion which is still further increased by the kinetic eiect of the draught tangentially admitted through tuyres 28.

The fire-crown I8 is supported by movable jacks I9 and its gas tightness secured by a gasket 23.

Smoke-tubes I2 contain sweeping-elements consisting in blades 32 connected to controlling rods 33 accessible from outside and allowing for said elements to be subjected to a rotary and a sliding movement even during service.

A manhole 34 placed opposite a free space pro- 38. The ow of smoke may be adjusted by means i of a damper 43: in service, through the fan, or, when the latter is stopped, through a by-pass 42 leading directly into the funnel.

The boiler also comprises safety-valves 4S and a steam exhaust 45 supplied with a water-trap 41.

The part played by primary hearth I!! is not to ensure total combustion, but merely the transformation of the fuel into gaseous compounds of indifferent quality, whose combustion is adequately completed in the Secondary hearth II next to the former. therefore operate with a thick layer of fuel.

Crown 5 forms an annular chamber within which a ring of stagnant ash is produced. This arrangement achieves the purpose, first, of protectin the row of rivets 4, second, of creating in g bular hearth. Feed of this distributor is secured the gas-discharge a loss of head along the wall which results in a more uniform distribution of combustion over the total section of the hearth.

The gases discharging from the primary hearth This primary hearth may are mixed with the secondary draught and a spin VVj;

is imparted to this mixture, first, through the surface effect of the tangential inclines 21, second through the kinetic effect of the secondary draught entering tangentially through tuyres 25.

The air required for secondary combustion may be provided with the excess air from the primary hearth, by the draught entering through tuyres 26 and by the air let in through additional inlet 28. In certain cases of service, for instance in the event of a thin layer of fuel or of a dry-burning fuel, the required amount of secondary air may be very small, and consist entirely of the excess air through the primary hearth.

The spinning mixture of combustion gases then passes through the diffuser 25 where the combustion reactions are accelerated due to its reduced sectional area and the very high temperature of its walls.

Lastly, the gases reach the tubular-hearth 'Z4 where, due to the high temperature of its walls, secondary combustion is completed under satisfactory conditions.

Moreover, the high temperature of the tubular hearths walls ensures a high transfer of radiant heat onto the heating surface (casing or heat transferring element 1) which encircles it.

This heat radiation onto a cold surface results at the same time in limiting the tubular hearths temperature to a Value consistent with satisfactory maintenance.

The combustion gases discharged from tubular hearth 24 flow through annular chamber 20, between the tubular hearth and the casing l whose total thermal transmission coeicient, due to radiation from tubular hearth 24 and to convection by the gases, is thus comparatively high.4

The gases enter chamber 53, then ow through smoke-tubes I2, smoke-box 35, and are sucked by fan 31 which then drives them to stack 39.

The smoke-tubes may be swept during service by operating from the outside rods 33 controlling sweeping elements 32.

Heat production may be adjusted by operating damper 43.

Fig. 5 represents by way of example a horizontal boiler carried out according to the invention.

Referring to this ligure, |3| is the boiler drum, supplied at its lower portion with a tubular hearth |32 arranged inside at horizontal flue |33 closed at its rear end by a domed head-plate |34; a space I4| is provided between the tubular hearth and the flue to allow for the free circulation of the hot gases. Above flue |33 two smoke-tube nests |36 and |31 are arranged, opening at the back into a chamber |33. Tube nest |36 opens in front into a chamber |42 and tube nest |31 into a chamber |43, from which a pipe |44 leads olic for the discharge of the gases.

Chambers |38, |42 and I 43 comprise doors |45, |45 and |41 respectively, permitting access.

Tubular hearth |32 which is made out of cast iron or stainless steel comprises in front, primary hearth |48 ending in a fore-hearth |49 and shown equipped with an automatic stoker |52.

The rear portion of the tubular-hearth comprises the secondary hearth consisting in a secondary draught distributor, a diiluser and a combustion-chamber. The secondary draught distributor |53 comprises nozzles I 54 directed approximately according to a tangent to the tuby a piping |55 carrying an adjusting device |56. Diffuser |51 is made out of refractory material and offers e, reduced cross-sectional area to the flow of gases. rPhe combustion chamber of the secondary hearth is formed by space |58 placed at the discharge 0f diffuser |51.

This boiler operates in a manner similar to the one previously described.

Water is poured into the boilers drum, 'and flue |33 as well as both tube nests |35 and |31 are immersed.

The gases produced in primary hearth |48 are mixed with the secondary air which imparts to them a spinning motion together iwith a violent mixingeiect and they are completely consumed in secondary hearth |58. The yconsumed gases having been discharged from the tubular hearth circulate in the annular space I 4|, reach chamber |42, flo-.v through the tube nests |35 and |31 towards the boilers face and pass into smoke box |63, whence they are evacuated through pipe |44 into the stack or into an economizer or air-heater, if need be with the help of a lan or other induced draught device.

Ratio of CO2 in the consumed gases is kept at a suitable value by means of an adjusting device |58.

The spin imparted to the gases at the entry of the secondary hearth can be amplified by means of tangential or helicoidal walls or inclines made out of refractory material and arranged on the fore-hearth H19 or the diffuser l5?.

The apparatus according to the invention could likewise be arranged for the heating of a gaseous fluid and, in that event, for use as an air-stove. An example of this is typified in Fig. 6 in which primary hearth 29E is shown supplied with a grate with steps 232 automatically fed by gravity with fuel from a feeder 293 and comprising an ash-removing device 206i.

According to the heat output desired, an adjustable valve 295 distributes the total |amount of air required for combustion and consisting of primary air coming through the grate and secondary air which is let in above the primary hearth through a channel 2923. An adjusting dev ice 291 ensures a suitable proportion of secondary `air according to the type of fuel employed. By means of this arrangement, it is possible, automatically and at all outputs, to maintain approximately constant the ratio of secondary draught and consequently to maintain the CO2 ratio in the smoke at a suitable value.

rihis results from the fact that by said means,

the ratio of loss of head and consequently of the ow of primary air through the fuel layer to the flow of secondary air through adjusting device 291 is kept appreci'afbly constant, and that is true whatever may be the degree to which valve 295 is opened.

The secondary hearth consists of:

Mixer 29S, out of refractory cast iron, comprising tangential blades imparting a spinning motion to the mixture of secondary air and gases from the primary hearth.

Diffuser 299, out of refractory material, whose reduced sectional area and walls at very high temperature contribute to the satisfactory evolution of the combustion reactions.

The tubular hearth 219, in which the combustion reactions are completed and @whose Walls which are at a very high temperature radiate heat onto the encircling heating-surface.

This heating-surface, constituted by flue 2i i, receives the heat radiated by the tubular hearth and transmits it to the air circulating along its inner and outer surfaces.

The extended tubular hearth comprises cooling ns 212 on its inner surface and cooling fins 213 on its outer surface, by means of which the gases are more readily stripped of their heat content. The gases are discharged directly through a nozzle 214.

The neighbouring air is heated by circulation between the tubular hearth ZID and the flue 2H and around this ue.

The invention is of course not restricted to the types of embodiment herein described land represented, which have been given solely by way of example. This apparatus can be applied to any heating appliance beside those mentioned above, including stoves, furnaces, drying ovens, etc.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A heating apparatus comprising a cylindrical outer body adapted to contain a fluid to be i heated, a primary hearth, a metallic tubular hearth within said outer body and through which combustible gaseous compounds evolving from said primary hearth are |adapted to.; flow and vto b'e completely burnt, a diffuser of refractory material disposed between said primary hearth and said tubular hearth, said diffuser having tangential inclines thereon for imparting to said gaseous compounds a rotary motion, and nozzles opening tangentially within the wall of said diffuser for introducing secondary air of combustion into said tubular hearth, a, chamber surrounding said tubular hearth and through which chamber the gases evolving from said tubular hearth are adapted to flow, and a heat transferring element directly subjected to the heat radiation from said metallic tubular hearth, said element being in contact with the i'iuid to be heated.

2. A. heating apparatus comprising a cylindrical outer body adapted to contain the fluid to be heated, a primary hearth, means for introducing into said primary hearth primary air to support incomplete combustion, a metallic tubular hearth within said outer body and through which tubular hearth combustible gaseous compounds evolving from said primary hearth are adapted to iiow and t0 be completely burned, a diffuser of refractory material disposed between said primary hearth and said tubular hearth, said diffuser lying within said tubular hearth, tuyres disposed immediately below said diffuser and directing secondary air tangentially into the gas flowing from the primary hearth to the diffuser, a chamber surrounding said tubular hearth and through which the gases evolving from said tubular hearth are adapted to flow, said chamber lying in direct heat transfer contact with said tubular hearth, and a heat transferring element enclosing the top and side wall of said tubular hearth and being directly subjected to the heat radiation from said metallic tubular hearth, said element being in contact `with the fluid to be one wall of said chamber.

3. A heating apparatus as claimed in claim 2 in which a refractory vault is disposed below said diffuser in close proximity thereto, said vault having tangential iniclines directing the now of gases into said diffuser, said tuyres being disposed between said vault and said diffuser.

MARCEI.. CYPRIEN l KUCZEWSKI DE PORAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 32,731 Willett July 2, 1361 558,167 Morgan Sept. 22, 1896 1,929,998 Benjamins June 18, 1912 1,296,194 La Cour Mar. 4, 1919 1,438,531 Cruse Apr. 1, 1924 1,734,310 Taylor Nov. 5, 1929 1,903,313 Johnson Apr. 4, 1933 1,943,622 Piatt Jan. 16, 1934 1,963,358 Foltz June 19, 1934 1,989,424 Morgan Nov. 13, 1934 1,995,185 Macchi Mar. 19, 1935 2,145,565 Curtis Feb. 7, 1939 2,244,869 Pascale June 10, 1941 2,264,226 Toner Nov. 25, 1941 FOREIGN PATENTS Number Country Date .594 Great Britain} Jan. 14, 1358 Norway f `53,2555 Nov. s, i933 

